Thursday, November 10, 2011

Engineering Drums Part Two: Tuning

Tuning drums is as much art as science. Drums vary tremendously from kit to kit with all the various materials (maple, birch, poplar, aluminum, brass, copper...), to various sizes, and ratios of diameter to depth, all of which affect the way you'll tune the drum to get the sound you're after. Rather than try to give anything close to an exhaustive lesson on tuning drums (which would be a book, not a blog post), I will give very basic tips that can be broadly applied, and also try to clear up a few misconceptions shared by both drummers and engineers regarding tuning. Keep in mind I offer these suggestions with the assumption that you are working with good drums with clean, true edges and rims, good heads... you get the idea.

Firstly, when putting heads on drums finger tighten each key rod only, taking care to make sure the head and rim stay centered on the drum (there is a little 'play' in the head when it's totally loose). When it is evenly finger tightened (and the head is snug), use a drum key to begin turning each key rod 1/4-turn at a time criss-crossing the head. Here is a picture showing the lug tuning order for a variety of common lug arrangements.

Sticking with this back-and-forth approach around the drum keeps the head from pulling too much to one side, allowing for more even tuning.

After each set of 1/4-turns tap the head about an inch in from each lug to check the pitch. Thinner heads will have more overtones, which can make hearing the fundamental a little tricky. If this is the case just lightly touch the center of the head with a finger, and the overtones will be well-controlled. Tap near all lugs and determine which are lower, and bring them up with slight turns until each lug shares the same pitch. Then another 1/4-turn for each lug, and another balance. Continue until you reach the pitch you want.

Always tune up, not down. If you find that you need to go lower, loosen the lug more than you intend, and then bring it up to where you want it. Ending with a clockwise turn stabilizes the tuning more than counterclockwise turns.

I generally tune toms near their midrange (which often only takes a full-turn of each key rod past finger tightening). The midrange is where the drum tends to have the most tone and sustain. Generally, sustain is a good thing in sound reinforcement as it can be controlled with dynamics processing if it's a bit much, but it's very difficult, if not impossible, to add sustain (yes, you could use compression to add sustain, but then you'll be processing all the bleed that the tom mics have, creating an entirely new set of problems. I recommend getting the most sustain from the drum itself to simplify your life).

Tuning toms above the midrange shortens the decay, and makes the drum's tone brighter. Tuning below the midrange shortens the decay and makes the tone darker. Basically, the midrange with where you have the most sustain. Go above and you choke it, go below and the head is too slack to achieve full resonance.

And, for clarity, when I talk about sustain or decay, I mean effective or perceived sustain or decay. When you're close to the drums you can hear them all resonating easily, but the practical sustain is that which is perceived by the listener who is across the room or by that which projects through the other elements in the mix. Larger toms can fool you into thinking the decay is too long (larger drums resonate longer!), but in the context of a mix, this is rarely the case.

If you have a kit with lots of toms and want to create a bigger pitch difference between them, you could tune the smallest tom a little above its midrange, and the largest tom below its midrange with a tapered approach between them. This approach helps define the pitches a little better, and the effect of these alterations create a smooth transition from brighter high toms down to darker low toms.

Tuning batter and resonant heads to the same pitch will make toms punchy with a shorter decay. Tuning one head higher than the other can increase resonance and often emphasize a 'bend' in the tone from attack to sustain. Some folks like to make the top tighter than the bottom, while others prefer the other way around. I've had success with both, depending on the dimensions of the drum, but it requires a little patience and experimentation to figure out what works best for each drum on the kit you're working with.

The snare drum is a rather odd beastie in that its bottom edge has a snare bed cut into it's edges at opposite ends under the snare strainer and butt. This bed, usually 2-3 inches wide at each end, causes uneven pressure on the bottom head that keeps it from resonating the way heads do elsewhere on the kit. For this reason I generally tune the bottom head using thumb pressure, that is, using my thumb I press on the head an inch in from each lug to determine how tight the head is. After much experience I can tell very closely how matched each lug is. Keep in mind that at the lugs immediately adjacent to the snare bed, the head will tend to give a little more. Don't try to match the tension of these lugs to the rest of the head as this variance helps the interaction of the head with the snares.

I recommend making the snare side head rather tight (the equivalent of a few full turns of each key rod). I want it to give a bit with firm pressure, but I want it well above the midrange. With the bottom head loose the snare will lack tone and will sound unpleasantly snarey (is that a word?) and flat. With it nice and tight you will have crisp snare response and plenty of tone.

Now, to clear up some misconceptions:

Firstly, many folks think that snare buzz is bad, and that they must tune the drums to where the snares don't respond sympathetically when any of the other drums are struck. Unless the buzz is extreme this isn't really a practical problem (not to mention that truly getting rid of it is practically impossible to do). The bit of snare buzz that happens with a well tuned kit just makes the kit feel more complete. This isn't the 1980's, where we're using drum machines with samples of individual drums with zero interaction. Modern drum sounds rely heavily on overhead and room mics to give the overall kit a cohesive sound, and the residual snare response is a big factor in that. As a matter of fact Yamaha's top-of-the-line electronic drum kit features a sample of snare buzz that plays (in the output of the snare channel) when each of the other drums on the kit are struck. The purpose of this is to better emulate the response and interaction of an acoustic kit, and the effect is convincing.

Secondly, it seems many folks believe that getting a crisp, fast 'snare' sound requires cranking the tension on the snare strainer so tight that only the strongest hits will actually get the snares moving. This choking of the snares only serves to make your snare drum come across as a tom, not a snare. Snares are the reason the drum sounds like a snare drum! Don't remove them from the equation by tightening them so much that they can't respond to anything but the loudest playing. For the drum to sound natural you need to have excellent snare response at all dynamics. I adjust my snare tension so that a very soft tap with the stick will have crisp, short snare response. I don't want the snares to rattle, just respond articulately with very soft playing. This sometimes results in snares decaying a little past the actual strike, yes, particularly if the drum has very little muffling and greater sustain, but it sounds more natural to the microphones, both near and far.

Thirdly, many people think that you have to muffle drums with moon gel or duct tape to get a rich 'studio' sound. The truth is, microphones don't quite hear drums the way we do. When each drum is miked closely, the mic is usually a couple of inches at most off the edge of the drum, pointed at the head. When was the last time you listened to drums with your ear that close? Likely never. It sounds quite different up close than it does when you're standing a few feet back from the kit. Yes, to some folks the overtones of drums (particularly with unmuffled, single-ply heads) can feel a bit overbearing, but avoid the temptation to pad them down before auditioning the kit through mics. You may be very surprised to hear that your perfectly tuned and muffled drums sound more like a collection of cardboard boxes upon playback through the studio monitors (and no, don't reach for an EQ to boost high mid frequencies trying to put life back in the drums.... GO OUT THERE AND FREAKING REMOVE SOME MUFFLING INSTEAD!!!)

[Wow... okay... deep breath,.... I apologize for that outburst. Where was I?...].

Oh yes... give the drums a chance to breath a bit and muffle only as needed.

On a related note, overtones from drums tend to get lost in the blend of other tracks within a pop mix. There's a lot of midrange information in pop music (vocals, guitars, keys, strings, effects, etc.), and those drums that sound too 'live' when solo'd will sound far more contained in the mix than you may expect. If you tame that life with muffling during tracking you may well find yourself struggling against 'cardboard box' syndrome when mix time rolls around.

Lastly, a big misconception I see people buying into is that to have a bright, poppy snare means to crank the top head up till the drum sounds like a timbale. When you do that you are robbing the drum's ability to resonate (which actually stifles the drum's overtones as well, making its tone.... wait for it..... less bright). So you wind up with a short, dead pop that more resembles a dull tabletop than a drum. For 'bright' snare sounds choose a metal shell drum, tune the bottom head tight and the top head a little above midrange. Tune it well and use little muffling, so its timbre can project like a good metal drum should. If you want more crack, have the drummer play rimshots instead of hitting the drum dead center.

This works for a wood drum too, but the sound, because of the softer material, will be a bit mellower, but still surprisingly crisp.

The rest of the 'sound' will be the mic you choose, its placement and your processing.

So that's about all I have to say about tuning. The art of tuning drums is extensive, and well beyond the suggestions that I have made here, but armed with this info, a good set of ears and a little patience you should be able to get where you want to go.

There is some variation between those tracks, but in general you're looking at a very slack top head with enough muffling to eliminate obvious ring. A 57 top and bottom would do nicely (the tone coming from the top, the snare sound from the bottom). On 'Vultures' the snare is compressed to give it some sustain (and perhaps distortion... hard to know exactly what stage that 'grit' in the sound is coming from). The sound is abrupt enough that it is surely gated (or some solid downward expansion with quick release). Sounds like some mids have been added to the bottom head to emphasize the snares (also gated), with the deep tone likely coming from the top head.

A good part of the 'punch' you hear is coming from a medium-ish attack that allows the low-mid edge of the attack through before clamping down. Quick release lengthens the sound (and then into the gate/downward expander).

Also notice the small room reverb that is rather liberally applied. It's very short, only a few hundred mSec at most with mostly early reflections.

Make sure the drummer is playing dead center of the head with no rim interaction (rimshot). This is a 'dead center' sound.

Similar stuff on the Hillsong track.

BTW, the snare doesn't have to be large, a 5x14 will do this nicely, even a metal shell. In fact, a metal shell can be cool for this as the hardness of the interior leaves the sound fewer places to be absorbed (compared to a softer shelled wood drum). So you can muffle it pretty strongly and still get some articulation between the hardness of the metal shell and mix of snare sound from the bottom head.